1. Field of the Invention
The present invention relates to the filed of integrated circuits, and more particularly, to devices for mounting integrated circuit packages.
2. Prior Art
Integrated circuit devices come in various shapes and sizes. Typically, integrated circuits (ICs) are fabricated on a semiconductor water. Each of the IC devices are then packaged in one of a variety of well-known packages. Typically, these packages are made from a dielectric material, such as ceramic, plastic or glass, in order to encase the IC within the package. In order to provide electrical connection to the electrical contact terminals of the IC, metallic leads are used. These metallic leads extend beyond the dielectric encapsulating material of the package. Prior art dual-in-line (DIP) packages, surface mount DIP packages which are also known as small outlines (SO), and flat packs are notable examples of packaging ICs.
In a typical application, these IC packages are mounted on circuit boards, modules, or sometimes directly onto the chassis or the casing of the equipment. In most of these instances the packages are designed to have the leads soldered to the attaching device, such as a printed circuit (PC) board. In such an implementation, the PC board is designed to have holes for receiving the leads of the IC package. The package is mounted on one side of the PC board with the leads extending through the holes to the other side of the PC board. The leads are then soldered for permanent physical and electrical connection to the PC board. This provides for a permanent attachment of the IC to the PC board.
A second technique for mounting IC packages onto a PC board utilizes surface mounting technology. Unlike the above described technique where the leads are inserted through the holes on the circuit board, surface mounted IC packages are mounted and soldered on the same side of the circuit board. Typically, solder pads are provided wherein the leads of the IC package are mated to its respective solder pad. The lead ends are formed to rest on the solder pad and are then soldered onto these pads.
However, a disadvantage of the above described techniques of soldering an IC onto a PC board is that it cannot be easily removed from the PC board. In order to provide for a less permanent affixation of the IC to the PC board, sockets are used on an intermediary between the IC and the PC board. When this technique is used, a socket is soldered onto a PC board and the IC is pressed onto the socket with the leads extending into contact portions of the socket. When a surface mount integrated circuit scheme is utilized, the socket is mounted onto the solder pad of the first side of the PC board, instead of having the leads of the socket pass through the circuit board. Then the surface mount IC is inserted into the socket for affixation to the PC board.
Although the use of IC sockets provides for a less permanent attachment of the IC package to the PC board, the additional lead length introduced, between the leads of the IC and the solder pad on the PC board, adds additional lead inductance which can be fatal in certain circuit applications. Furthermore, the IC socket still requires the use of solder to permanently affix the socket to the PC board.
It is appreciated then that a device for surface mounting an IC package onto a PC board without the use of solder or without the introduction of additional lead inductance would overcome the short comings of the prior art IC mounting techniques.